The present invention relates to polymer compositions comprising polyamide resins and polyolefins as main components, and more particularly to polymer compositions comprising polyamide resins and polyolefins as main components, which are excellent not only in heat resistance, chemical resistance and impact resistance, but also in antifreeze resistance and moldability, and further have remarkably improved Geer oven life and copper-contacted Geer oven life.
Containers such as radiator tanks of automobiles have been getting increasingly produced from plastics, for the purpose of reducing their weight. As plastic materials for producing such containers, polyamide resins are highly suitable because they are light and excellent in impact resistance, heat resistance, chemical resistance, etc.
However, despite the fact that polyamide resins, etc. are excellent in heat resistance, mechanical strength and long-term durability, they are generally poor in water resistance, moldability, chemical resistance and antifreeze resistance.
The above desired properties, which are insufficient in the polyamide resins, are generally possessed by polyolefins. Thus, various compositions based on polyamide resins and polyolefins have been proposed.
For instance, Japanese Patent Laid-Open No. 55-165952 discloses a polyamide composition comprising (A) 50-99 parts by weight of a polyamide resin and (B) 50-1 parts by weight of a modified polyolefin or a modified olefin elastomer, which is produced by grafting a polyolefin or an olefin elastomer with 001-10 mol % of at least one of alicylic carboxylic acids containing cis-double bonds and their functional derivatives. This reference also discloses the above polyamide compositions further containing an unmodified polyolefin.
However, the conventional polyamide resin-polyolefin compositions are extremely vulnerable to deterioration when heated for a long period of time particularly in contact with metals such as copper.